Three's A Party, Four's A Crowd
by Magic Beanstalk90
Summary: Prue Halliwell thought life couldn't get any better... until the fourth Halliwell sister arrives from an alternate reality, where Prue is dead and Paige is her replacement in the Power of Three, to inform them that a demi-god is reaching out through realities to steal Prue's power and destroy the Halliwell line. Pairing: Prue/OC
1. Chapter 1

The darkness began to fade and Prue became aware of the noises around her again. Struggling she peeled her eyes open and for a moment her vision was blurry until it cleared. She stared up at the ceiling as feeling returned to her body. She hurt... alot. She was lying on a hard wooden floor, pain radiating from her head and her chest. That would be from the demon's attack. _Shit, the demon!_

With a lot of effort she pulled herself up to sitting, the motion sending a fresh wave of pain through her head. She gritted her teeth against the agony and focused on her surroundings. Phoebe was on the floor a few metres away, unconscious and bleeding. Prue fought the urge to cry as tears threatened but she blinked them away and turned her attention to the rest of the room. It was a bombsite with furniture trashed across the room, the remnants of their magical battle. Piper was nowhere in sight. Panic darted through her and Prue forced herself to her feet. Limping slightly, she held a hand to her chest and moved to Phoebe's side. She knelt down beside her sister and felt her pulse. It was reassuringly strong despite the nasty cut running across her side. She shook her gently and when Phoebe didn't respond she cursed under her breath. With a sigh she summoned the last vestiges of her strength and picked her sister up, cradling her against her aching body. She half carried, half dragged Phoebe out of the house and out to the car.

After putting her gently into the back seat she climbed into the driver's seat and her head drooped wearily onto the steering wheel. She pulled out her cell phone and dialled a number she knew off by heart. The pain in her body was nothing compared to the ache she felt from the need to hear his voice. It rang a few times before cutting to answer phone. Tears welled up once again and this time she let them fall, stinging the grazes on her cheeks as she listened to him asking her to leave a message.

"Lucas, it's me. I... uh... we failed. He was stronger than we thought. He trapped us in the void so we couldn't use our magic and... he's got Piper. Oh god, he's got my sister!" The horror of the situation hit her full force then and she struggled to breathe. After a few seconds of hysteria she took a deep breath and pulled herself up straight. She continued speaking, hating herself for what she was about to say. "I won't be home when you get back from the hunt tomorrow. We have to find her Lucas and we can't do that from the Manor. We're going into the Underworld and I will tear it down piece by piece until I find her. I'm sorry but I swear, I will come back to you. I just... I need you to look after Leo and the boys for me while we do this. You're the only one strong enough to protect them while we're not around. If the demons know that Wyatt is unprotected they'll come for him. Keep him safe for me baby. I love you. I'll come back to you." She cut off the phone call and dropped her cell into her lap. Sobs wracked her body as she gave herself over to the pain. After a few moments she felt Phoebe's arms round her shoulders. Prue clung to her, relief that she was alive making her cry harder.

"We're going to the Underworld?" Phoebe asked, unhappiness evident in her voice but there was resignation too. The demon called himself a demi-god of the Underworld and he would hide in the safest place for him, surrounded by his loyal followers. They had to go to him and fast, if they had any chance of getting Piper back. Prue nodded in reply. Phoebe gave her a quick squeeze and kissed her temple. "Let's get it over with then."

The last two weeks had been the hardest of her life. Two weeks of living in hell. Two weeks of hunting and killing demons. Two weeks of searching for Piper. Those two weeks were finally over. Prue sat on the ground, cradling Piper in her lap. Phoebe knelt beside her, brushing kisses all over Piper's face. None of them spoke, they simply felt. Prue held onto her sister tightly as she stared at the scorch mark in the centre of the cavern. She had no idea how she'd done it. Despite everything they'd done in the past fortnight she had no idea where she'd gained the power from within the void.

During their time in the Underworld Prue and Phoebe had pushed themselves to the limit in their search for their sister. They stopped being wives and in Phoebe's case, a mother. They stopped themselves feeling anything for their family far away. They simply gave themselves over to the hunt. They performed magic they didn't know they were capable of. They fought in ways they'd never even thought of before. But when they found Piper and the demon they stepped into a void, a place devoid of magic. They couldn't summon their own personal powers nor tap into the power of three. They were powerless against a demon who could summon strength from the earth. But somehow, seeing Piper helpless and broken had broken a dam within Prue. All the feelings she'd pushed to the side for the past two weeks suddenly came rushing to the surface, pouring out of her in waves of power. The telekinetic blast she released broke the void, releasing magic back into the cavern. It also killed the demon. When Phoebe examined him she said that every bone in his body was broken. He burst into flames a second later. Piper and Phoebe had stared at her in shock and horror before they collected themselves. The sisters embraced then; finally realising they were reunited again.

"Where are my boys? Leo?" Piper's voice was small and weak but the longing in her words spoke volumes.

"They're safe. Lucas is watching over them." Prue assured her.

"Take me to them." Piper's command was an easy one to grant. Prue nodded at Phoebe and was filled with an overwhelming need for home as she listened to her sister recite the words of the transportation spell.

Seconds later, the white lights cleared and the familiar layout of the Halliwell Manor's living room came into view. Piper burst into tears and tried to scramble to her feet but she fell to her knees, weakness overcoming her.

"LEO!" Piper screamed the sound echoing throughout the house. The sound of footsteps could be heard from the kitchen and Prue smiled. Closing her eyes, she whispered. "We're home."

The Halliwell Manor was eerily quiet but Prue wasn't afraid. She soaked it up, letting the feeling of home seep into her soul and soothe the cracks she'd developed over the past fortnight. She stared into the darkness, her mind too wired to be lulled to sleep. She'd spent too long resisting it that it wouldn't come easily to her now and she had a feeling that her sisters would be feeling the same in their respective bedrooms. Prue smiled at that thought. Despite the fact that Phoebe and Prue had moved out a couple of years ago, this was always their home. It was the heart of their family and at times of crisis where they always returned. It was their haven at times such as now when it comforted them to stay together, sleeping under one roof and trying to forget the events that had gone before. But Prue couldn't forget, not yet. It went round and round in her mind.

_What did I do? How did I do it? No one can summon magic within a void... No, that's wrong. Gods can summon magic within a void. But she wasn't a god. She was just a witch. Granted she was a Charmed One but that wasn't in the same league as godhood. Was it? _

"Are you going to turn that brain of yours off and come to bed or do I have to find a way to distract you?"

The sleepy male voice that came from the bed sent a quiver of happiness running through her. She turned to look over at him, the shadows preventing her from seeing his features from her seat in front of the dressing table but she could see his figure pushed up on his elbows. She could only imagine the sexy smirk on his face and the twinkle in his eyes as he looked over at her.

"I think you found a wonderful way to distract me earlier tonight." She wiggled her eyebrows at him, her thoughts returning to the passionate reunion they had enjoyed earlier that night.

"Well clearly it wasn't enough otherwise you'd be in bed with your loving husband instead of stressing over nothing."

"It's not nothing though is it?"

He obviously heard the emotional hitch in her voice because he instantly got out of bed and moved to crouch beside her. He put a hand over hers and brought it up to his lips, kissing her fingers softly.

"It's nothing compared to this. It's nothing compared to our love, compared to your sisters, to our family and our lives. We have nothing to worry about that can't wait until morning."

"We?" She asked, feeling slightly reassured.

"It's always going to be 'we' Prue. From the moment I met you, we've been 'we' and always will be."

"The moment I met you I thought you were a demon." She reminded him.

"The moment I met you I thought you were mine. In a thousand years I've never met anyone like you and I knew you'd be the one."

She leaned forward and kissed him softly, savouring the taste of his lips. Pulling back slightly she looked into his big blue eyes and smiled.

"You say the sweetest things to get a woman into bed."

He let out a quiet laugh before replying.

"Is it working though?"

Instead of answering she took his hand in hers and got to her feet, pulling him up with her and led him over to the bed. She pushed him back onto the mattress and eased herself down beside him. Running her hands over his body, she delighted in the feel of his hard muscles clenching beneath her touch.

"How exactly were you planning on distracting me this time?"

He didn't need any other prompting as he pulled her tightly against him, his lips finding hers. She gave herself over to the feel of his body as she lost herself in the memory of their lives together, right from the very first moment.


	2. Chapter 2

Laughter echoed through the Halliwell Manor. Children ran through the rooms, giggling and screaming whilst the adults watched them happily from the dining table. Phoebe held onto Coop's hand whilst they watched their 18 month old daughter Penelope Joanna trying desperately to run after her older cousins. Wyatt and Chris were chasing each other round in a very energetic game of tag that made their parents exhausted just to watch them. Piper was resting her head on Leo's shoulder whilst he fed her forkfuls of cake and making her chuckle when he missed her mouth so she had a chocolate smudge down her nose. Prue watched them all, leaning back into Lucas's embrace. His strong arms were wrapped round her and every now and then he brushed kisses into her hair. Contentment filled her and she couldn't think of a time that she'd ever been happier. Family was everything to Prue and after the events of the last two weeks it had become doubly important to her.

"So who's on washing up duty?" Piper asked and was greeted by a chorus of rejections. They laughed and Piper rolled her eyes. "Can I remind you of who spent all day creating this wonderful feast?"

"You say it like it's a chore. You know that you're never happier than when you're elbow deep in a hundred different ingredients." Prue told her.

"Doesn't mean I enjoy the mountain of clean up I have to do afterwards."

"Do you think there's a spell in the Book of Shadows for dishes?" Phoebe wondered.

"No! No magic or spells or demons for at least a month! I'm all magic-ed out." Prue pouted and buried her head in Lucas's shoulder.

"Besides if there was one we'd have found it by now and we'd be more like Bewitched than Charmed Ones." Piper said, wiping chocolate off her nose and onto Leo's shirt.

"I love that show." Phoebe sighed.

"We know!" Her sisters exclaimed before all three of them collapsed into silly giggles.

At this point Lucas maneuvered Prue so she was sitting back on her own chair comfortably before getting to his feet.

"Ok guys, I think we should leave the girls to their womanly chatting." His words earned him a swat on the thigh from Prue before he continued. "Let's go be macho in the kitchen and do the dishes."

The girls laughed as the other husbands agreed and began clearing the table.

"I've got some very macho aprons hanging on the basement door for you." Piper called after them and was answered with a resounding door slam which had the sisters giggling again.

"What other family night surprises do you have in store for us tonight Piper?" Phoebe asked, pulling her knees up to rest her chin on them.

Piper seemed to contemplate the question before a mischievous grin appeared on her face. Prue had a horrible feeling that tonight was going to be a disastrous repeat of Pictionary night but her fears went unconfirmed. Before Piper could speak a bright white light filled the room and eerie whistling screeched around them. All three of them leapt to their feet. Piper and Phoebe ran to their children, shielding them with their bodies whilst Prue stood between them and the figure that was slowly appearing in the centre of the light. She shielded her eyes as she tried to make out the person within. Friend of foe, she really wasn't sure but she stayed alert in case it wasn't a visitor they were happy with. The men came bursting through the kitchen door, Lucas leading the way. He'd already conjured fire in the palm of his hand and was ready to use it if he needed to. Prue couldn't be prouder of her warrior husband but she turned her attention away from him and onto the figure that was fully visible now.

The light faded and the whistling died away leaving a woman standing in their dining room looking very superfluous after the method of her arrival. Prue watched her carefully, looking for any sign of aggression but she simply gaped around the room until her eyes settled on Prue. Her expression changed into a mixture of emotions that Prue couldn't identify before the other woman spoke.

"Oh my god. It's you."

Prue raised an eyebrow at this statement.

"Yeah, it's me. Now who the hell are you?"

The other woman smiled before replying.

"I'm your sister."

Three Halliwell eyebrows were raised in unison now as they stared incredulously at this woman.

"Explain." Prue demanded, crossing her arms as she settled into her 'I am the oldest sister, you will obey me' pose. This did nothing to intimidate her, however, and she simply smiled with a touch of melancholy on her lips.

"You're just like they said you'd be. I never... I've wanted to know you for so long. I've been trying so hard to make you proud and I just... I don't know what to say now."

Prue was shocked to see tears well up in the other woman's eyes. She shared a confused look with her sisters who seemed as flabbergasted as she was. Turning back to face her, she was relieved to see her shaking her head and regaining her composure. She didn't want to have to deal with a witch who was obviously delusional and hysterical to boot.

"Why don't you sit down and tell us exactly what you're doing here and why you think we're your sisters." Piper told her in a soft voice that Prue had heard her use many times before with her children. The other woman gave her a strange look, almost as if she was comforted by Piper's mothering and did as she was told, dropping into a seat at one end of the table. The sisters sat at the other end, looking down at this intruder, whilst the men moved from the kitchen doorway. Leo and Coop took the children upstairs but Lucas remained, standing behind Prue. He was no less menacing than before but at least he'd put out the flame he'd been carrying around.

"Start from the beginning." Piper told her. The other woman took a deep breath and began speaking.

"My name is Paige Matthews."

"Another P. Imagine that." Phoebe muttered to her sisters.

"I was adopted as a baby and raised by wonderful parents who died when I was a teenager. As an adult I decided to look for my birth parents and for a while I thought that maybe... Patty Halliwell was my mom."

Prue felt her hand clench on the table cloth at the mention of her mother. The way this woman was talking was the same as blasphemy to her ears but Lucas's reassuring hand on her shoulder kept her emotions in check and she refrained from speaking.

"I never did anything about it after I found out she was dead, I just carried on with my life. Until..." She sighed and rubbed a hand over her face, obviously struggling to continue. After a few seconds of silence she began speaking again. "I saw an obituary in the paper, announcing the funeral of Prue Halliwell."

The sisters all tensed and the pressure on her shoulder increased as Lucas growled softly behind her.

"I don't know why I went but I'm so glad I did. I met Phoebe, later on she saved me from Shax and I discovered the truth. Patty Halliwell was my mother and her whitelighter Sam was my father."

"What?! Mom NEVER had a child with Sam." Prue spat out angrily.

"Not here they didn't. Not in this world. In my world Patty and Sam were together but their love was forbidden by the Elders."

"Pfft, why doesn't that surprise me? They put me and Leo through hell, why not Mom too?" Piper muttered angrily causing Paige to smile at her.

"You and Leo are the same in any world. Anyway, when she gave birth to me they were scared that the Elders would punish us, all four Halliwell children. So they gave me away. It took me years to find you and I was already too late. You were gone." She was speaking directly to Prue now. "I've never had the chance to meet you, to talk to you. We avenged you though. My first act as a Charmed One was to vanquish Shax."

At her words Prue felt a feeling akin to pride welling up inside her before she pushed it down. She had no idea whether this woman was telling the truth or not.

"So why are you here? In our world? I'm guessing you don't exist here right?"

Paige shook her head at Phoebe's last question before answering the others.

"In our world we've managed to vanquish most of the major threats in the Underworld, like the Source, the Triad... even Barbas is out of our lives. We were living semi-normal lives with children and husbands."

"Like us then." Prue stated, thinking of the battles they'd endured to allow them some freedom to live a normal life. Until the demi-god had shown up.

"We were wrong to think we were safe. There was a demon; actually a god is probably more accurate. He kept himself hidden in the very depths of the Underworld until we'd destroyed all those in power and he could take control of the chaos left behind."

"Wait, we know who you're talking about. Draws power from the earth, can create magical voids at will?"

Paige nodded and Prue continued.

"Well he's gone. I vanquished him five days ago."

Paige's eyes widened for a second before she spoke.

"The threat from your world may be gone but the one from ours isn't. He's too strong for the Power of Three or anything else in our world. We can't stop him yet he hasn't even tried to attack us. He's simply slaughtering his way through demons, stealing their powers as he goes."

"Sounds like he's doing you a favour." Phoebe snorted.

"He's searching for something. And I don't think we're going to like the consequences when he does." Paige informed them.

"That still doesn't explain why you're _here_, in our world."

"Because... because we think he's searching for you Prue."

"_What?!"_ The exclamation was echoed by the four voices opposite Paige.

"We've had some help from the magical community and we found out that he's gained the ability to walk between realities. He was in contact with the god from your world and I think they planned the attack on you. They needed you to tap into that power which you obviously did if you managed to vanquish him."

"What power?" Prue spoke with an emotionless voice, her mind in turmoil but she refused to show it.

"We're not sure. All we know is that you were destined to inherit a great power, we don't know why and we don't know what it's for. All we know is you've got it and he wants it. I was sent here to warn you and help you. Piper and Phoebe would have come but they're looking after the kids and... it's too hard for them, to see you then have to go back to a world where you aren't."

Prue refused to feel anything for those sisters in another world, her sisters who were no longer together.

"How do we know you're telling the truth?" She asked instead. In answer Paige simply held out her hand and in a flurry of orbs the candlestick in front of the sisters disappeared before reappearing in Paige's hand.

"I inherited your power of telekinesis with my own whitelighter twist. I have whitelighter powers as well as Charmed Ones."

"That proves you're a witch. It doesn't prove you're our sister."

"Prue..." Piper spoke as if to ease Prue's aggression but was cut off as Paige got to her feet and moved down the table until she was standing in front of them.

"Hold hands." She commanded them. With a few seconds hesitation they did as they were told. Paige took Piper's free hand and reached over to take Phoebe's. Tension thrummed through all of them but as soon Paige's hand touched Phoebe's everything changed. A soft blue light flowed down from the ceiling and power burst forth to touch all of the women. They all stared at each other as a feeling of completion filled them. From worlds apart, they were joined and they all knew it. It was a feeling that came from deep within their soul and when the light faded, they all had tears in their eyes. Instinctively all three of them stood and enveloped Paige in a bone crunching hug. It was a strange situation but in that moment it didn't matter. They were sisters and that was what was important right then.

After a few moments they pulled apart, wiping their eyes. During their bonding moment, Lucas had gone upstairs and left them alone now that he knew they weren't in danger. Prue was grateful to him for that.

"What happens now?" Phoebe asked, her voice still thick with emotion.

"We have to find out more about this god. Maybe there's something in your world that we couldn't find out in mine. We need to stop him before he gets to Prue." Paige stepped away from them, clearly ready to go into battle but Prue reached out and took her hand.

"That's tomorrow's problem. Tonight I want to get to know our baby sister. I want to know everything."

Paige smiled, tears threatening in her eyes again. Piper and Phoebe obviously agreed with Prue as Phoebe put her arm round Paige's shoulders while Piper put an arm through Prue's. Demons could wait. Family was more important now.


End file.
